Sheet metal flanger of the roller type



Sept. 3, 1957 C. F. ENGEL SHEET METAL FLANGER OF THE ROLLER TYPE FiledMarch 19, 1954 nvwzzvrox. CHARLES F. ENGEL ATTORNEY SHEET METAL FLAN GEROF THE ROLLER TYPE Charles F. Engel, Randolph County, Eli.

Application March 19, 1954, Serial No. 417,283

16 Claims. (Cl. 153-29) This invention relates to sheet metal flangingmachines, and is of particular value for turning flanges on pieces ofsheet metal ducts such as are used in heating and airconditioninginstallations.

Duct work includes many so-called transition sections, as are used, forexample, to continue ceiling ducts down under beams. In such sectionsthe duct is usually lowered, broadened and flattened. This requirescheek pieces of reversed curvatures, which must be flanged forattachment to the other duct portions. No tools have heretofore beenavailable by which such pieces could be flanged by even semi-skilledworkmen.

A principal object of the present invention is to provide a new methodof employing flanging rolls to turn flanges on sheet metal work pieceswithout guiding, regardless of edge curvature, thus rendering theflanging operation atcnt simple enough to be performed by unskilledhelp. Other objects include: providing a flanging machine from whichwork pieces may be readily withdrawn, and one which adapts itself tosubstantial variations in material thickness and rigidity; eliminatingthe need for fixed follower rolls; and if any following pressure is tobe mechanically applied, then changing the point of application and theamount of follower pressure automatically according to the curvature ofthe edge of the work piece.

The present invention should be distinguished from flanging machinesheretofore in use employing fixed guides on both the inlet and outletsides of the hanging rolls. In such machines a heavy pressure is exertedagainst the guide at the outlet side of the rolls as well as the guideat the inlet side. Such machines cannot flange edges of varying orreversing curvature. If such fixed guides are removed, a piece to beflanged must be guided shillfully through the flanging rolls, or else auniform flange will not be formed.

Utilizing the present invention, however, the sheet material passingthrough the flanging rolls is guided by the very contour of the sheetedge. ment illustrated, this is accomplished by rolls having marginsoverlapping substantially in a plane perpendicular to the axes ofrotation, the overlapping surfaces being spring-urged toward each other,one surface having a greater coeflicient of friction than the other. Asheet metal work piece pressed between such surfaces will tend to rotatewith the roll whose surface has the greater coefiicient of friction,such rotation being opposed by contact of its edge against a fixed wiperguide at the inlet side of the rolls.

While this construction eliminates the need for guiding a work piece, asteadying follower force, to be exerted at the outlet side of the rolls,is usually necessary. Such required force is greater for convex edgecurvature than for concave curvature. This phenomenon may be explained,at least in part, as follows:

When a flange is formed on an edge of concave curvature, its outer edgeis elongated and permanently set in tension. In contrast, a flangeformed on an edge of In the embodiice in which case there appears to bea greater spring-bac tendency to be overcome.

Since follower pressure is to be applied to the edge of the work piece,any change in curvature of the edge will change the necessary point ofapplication of such follower pressure. The total amount of followerpressure to be exerted is usually so little that a semi-skilled operatormay exert it merely with his finger. However, the machine hereindescribed includes a follower roll which positions itself automaticallyand varies its pressure responsive to changes in contour of the piecebeing flanged. Thus a workman may start the piece to be flanged in themachine and release his hold on it at once, to pick up the next piece.

In the accompanying drawings:

Figure 1 is a plan view of a flanging machine embodying the presentinvention, showing the work table thereof partly cut away and thefollower roll mechanism in one extreme position, the other extremeposition being shown in phantom lines.

Figure 2 is an elevational view of the flanging machine shown in Figure1.

Figure 3 is a fragmentary elevation of the side of the machine oppositethat shown in Figure 2.

Figure 4 is a fragmentary vertical section taken along line 4-4 ofFigure 2.

Figure 5 is an enlarged fragmentary view taken along line 5-5 of Figure2.

. Figure 6 is a still further enlarged fragmentary view of the regionindicated by line 6-6 of Figure 2.

The drawings illustrate a steel work table, generally designated 11,having a heavy sheet steel table surface 12 and supporting legs 13.Beneath such table surface is mounted a source of rotary power,preferably an electric motor 14 and a V-belt 15, which drives a drivenwheel 16 secured on one end of a horizontal shaft 17, the assembly beingsupported by a shaft support bearing 18 horizontally mounted beneath thetable surface 12 on a rigid steel support frame 19. At the end of theshaft 17 opposite the driven wheel 16 is a worm gear 20 which mesheswith a worm-driven sprocket 21 secured to the lower end of a principalvertical shaft 22. The general relationship of the parts is shown inFigures 1 and 2, while the principal shaft 22 and the working partscoupled thereto, are shown in section in Figure 4.

Secured to the principal shaft 22 above the sprocket 21 is a drivingspur gear 23, which meshes with a driven spur convex curvature isshortened and ?set in compression,

gear 24 of the same pitch and diameter. The latter is secured to anddrives a supplementary shaft 25 which is mounted substantiallyvertically and parallel to the principal shaft 22. The principal shaft22 is mounted for rotation and supported by the support frame 19 bymeans of a principal vertical bushing 26 grasped within a principalouter cylinder 27. The cylinder 27 is maintained in place in alignedbores of the upper and lower support blocks 28, 28', which also supportthe supplementary shaft 25 in a second pair of aligned bores by means ofa supplementary outer cylinder 29 and supplementary support bushing 30.The supplementary outer cylinder 29 is supported in the upper and lowersupport blocks 28, 28 with a limited amount of clearance, and itsalignment is adjustable by means of two sets of alignment bolts 31 andstop nuts 32 arranged at ninety degrees from each other.

The upper end of the principal shaft 22 extends through and terminatesimmediately above the table surface 12 within a principal flanging rollgenerally designated 33 securely mounted thereon. This roll 33 has aknurled or coined perimeter roll surface 34 which, in the embodimentshown, is substantially cylindrical. The upper end surface 35 of theroll 33 has a similarly tooled outer margin 36.

Secured to the principal shaft 22 immediately beneath the principalflanging roll 33, is a subjacent collar 37 having a collar rim 38 whichextends radially outward im mediately subjacent the perimeter rollsurface 34 of the principal flanging roll 33. This portion of the collarrim 38 is smooth, in contrast to the perimeter roll surface 34 of theprincipal flangingroll 33, for which reason it is more readily made as aseparate collar rather than integral with the roll 33'.

The upper end of the supplementary shaft 25' likewise extends through abore in the table surface 12, and to it is secured a supplementalflanging roll 39,. having asmooth perimeter surface 40 normally heldimmediately above the surface 12. The smooth perimeter surface 40 issubstantially cylindrical. Its radius is substantially the same as thatof the coined perimeter roll surface 34 of the principal flanging roll33. As shown in Figure 4, its lower edge is normally adjacent the uppersurface of the collar rim 39 on the principal shaft 22. At its upperedge protrudes a radially-enlarged superjacent portion 41, whichpresents downward a substantially horizontal, smoothly machined,overlapping rim'surface 42. This overlaps the upper surface 35 of theprincipal flanging roll 33 a distance less than the latters radius, andis normally held closely adjacent it, separated by the thickness of thesheet material to be flanged.

The supplementary shaft 25 is so mounted in the supplementary supportbushing 30 as to permit not only rotation but also axial slidingmovement therein. In this description, the phrase normally held refersto the position during the flanging operation, which is its mostdownward position. The supplementary shaft 25 is held in this downwardposition by a compression spring 43, which is positioned coiled aroundthe supplementary shaft 25 and maintained in compression between theupper side surface of the driven spur gear 24 and the lower end of thesupplementary outer cylinder 29. Clearance between the overlapping rimsurface 42 of the supplemental flanging roll 39 and the upper endsurface 35 of the principal hanging roll 33 is adjustable by means ofthe shaftbottoming bolt and set screw 44, 44 which are mounted on aportion of the support frame 19 extending therebeneath, as shown inFigure 3. The lower end of the supplementary shaft 25 is reduced indiameter so as to penetrate and be supported by a lift bearing 45, asshown in Figure 4, which in turn is mounted in a support yoke 46. Thisyoke 46 is pinned between the tines of a lift fork 47 having a fulcrumpivot 48 through the forward portion of the support frame 19, as shownin Figure 3.

The table surface 12 has a comma-shaped cutout 49, as shown in Figure 5.Of the cutout 49, the circular portion 50 is of sufficient diameter toaccommodate the collar rim 38 beneath the principal fianging roll 33.Slotted outward therefrom, and extending any distance from sayforty-five degrees to one hundred twenty degrees in an arcuate pathcentered about the supplementary shaft 25, is the comma-tail cutoutportion 51, adapted topermit the swinging about the supplementary shaft25 of a follower roll 52 hereinafter described.

Beneath the supplemental flanging roll 39 and the table surface 12, afollower control sector 53 (preferably made of two thicknesses ofsheet-metal spot welded together) is mounted for limited rotary movementwith reference to the supplementary shaft 25. At the same radialdistance from said shaft as the center of the path of the comma-shapedcutout 49, there is mounted in the control sector53 an upstandingvertical follower pivot 54, which stantially this position when flangingsheet metal work pieces having convex curvature of radius nearly assmall as the radius of the principal flanging roll 33.

The control sector 53 has a grooved .arcuate edge 56 which guidinglyaccommodates a control cable 57 pinned to the control sector 53 at thatend of the arcuate edge 56 farthest removed from the principal flangingroll 33. The positions of the follower roll 52, control sector 53 andthe control cable 57 for forming a flange on a convex curved edge ofsmall radius, are shown in solid lines in Figure 1; their positions forhanging edges having concave curvature of small radius are shown inFigure l in phantom lines. For larger curvatures and straight edges, theposition assumed by these elements will be somewhat between the twoextremes shown in Figure l.

The control cable 57 leads in a path nearly tangential to the sectorsarcuate edge 56, over a pulley 58, located beneath the table surface 12adjacent its edge, as shown in Figure l, downward to the middle of adownward-e tending trolley clevis 59 mounting a trolley Wheel 60, whichrolls along a control bar 61. One of the ends of the control bar 61 ismounted on a horizontal pivot 62 secured to one of the table legs 13 ata height somewhat between the down position of the control bar 61, asshown in Figure 2 in solid lines, and its up position, as shown inphantom lines. These positions correspond to the two extreme positionsof the control sector 53, shown in solid and phantom lines,respectively, in Figure 1. An adjustable stop collar 63 on the controlbar 61 limits the permissible movement of the trolley clevis 59 towardthe pivot 62, and a movable weight 64 having a set screw 65 ispositioned at a selected distance along the control bar 61 on the otherside of the trolley clevis S9, limiting its permissible movement awayfrom the pivot 62.

The directions of movement of the principal flanging roll 33 andsupplemental hanging roll 39 are shown by the arrows in Figure 5, fromwhich it is evident that the follower roll 52 lies at the outlet side ofthe flanging rolls mentioned. Positioned at the inlet side thereof, andextending partly under the superjacent rim portion 41 of thesupplemental fiangiug roll 39, is a wiper guide abut; meat 66 securelymounted to the upper side of the table surface 12 and having a somewhatconcave wiper edge 67 which extends from said table surface 12 upward toa point approximately as high as the upper end surface 35 of the.principal flanging roll 33. While the precise posi tioning of the wiperguide 66 is partly a matter of choice and experience, its wiper edge 67leads inward to the flanging rolls 33, 39 fairly near the line of commontan gency thereof.

Secured to the edge of the work table 11 and having its upper margin inthe plane of surface 12, is a flange starter block 68 having a verticalnotch 69 extending downward from the table surface 12 a depth equal tothe depth of the flange to be formed. Before inserting a piece of sheetmetal into the flanging machine, its cornet is inserted into the notch69 and the body of the sheet metal piece is then bent over onto thetable surface 12. After a flange has been so started on the work piece,it is ready for feeding into the flanging machine. I

With the power engaged to drive the driven wheel 16; and the hangingrolls 33, 39 turning in the directions indicated in Figure 5, the workpiece with such started flange is fed into the machine in the followingmanner: the work piece is inserted so that its started flange is alignedfor entrance between the perimeter roll surfaces 34, 40 of the saidfianging rolls 33, 39; and the side of the body portion of the workpiece toward which the started flange has been bent is laid superjacentthe upper end surface 35 of the principal flanging roll 33. The startedflange on the work piece is brought adjacent the concave wiper edge 67of the wiper guide 66. Even before its started flange enters between thesaid perimeter roll surfaces 34,

40, its body portion is engaged and guided by and between the tooledouter margin 36 of the principal flanging roll ,33. and the. smoothlymachined overlapping rim surface 42 of the superjacent portion 41 of thesupplemental flanging roll 39. The started flange of the sheet metalwork piece is then drawn between the perimeter roll surface 34 of theprincipal flanging roll 33 and the perimeter surface 40 of thesupplemental flanging roll 39.

One novel feature is the overlapping smooth rim surface 42, urged by thespring 43, to press the work piece tightly against the tooled outermargin 36 of the principal flanging roll 33. The tooled margin 36 has asubstantially greater coeflicient of friction in rotation than does thesmooth rim surface 42. As a result, a tendency to rotate with theprincipal shaft 22 will be imparted to such work piece; and this isresisted by the wiper edge 67. The tendency to rotate steers the workpiece so that, regardless of changes in edge curvature, it is pressedsecurely against the wiper guide 66. The reacting force, exerted by thewiper edge 67 against the edge of the work piece, bends it as it passesbetween the said perimeter roll surfaces 34, 40, where the flangingoperation is completed.

The shaft-bottoming bolt and set screw 44, 44 at the base of thesupplementary shaft 25, permit adjustment of the flanging rolls 33, 39for material thickness.

The alignment bolts 31 and stop nuts 32 may be used to make slightadjustments in the alignment of the supplementary shaft 25. Thisalignment serves two purposes: to provide spacing between the perimeterroll surfaces 34, 40, and also to effect a slight degree of sidewardtilt to bring the overlapping rim surface 42 on the inlet side of theflanging rolls 33, 39 slightly closer to the upper end surface 35 thanon the outlet side. Both these adjustments affect the feed of sheetmetal work pieces into the flanging machine.

As was indicated in the general discussion preceding this detaileddescription, the mechanism so far described eliminates any need forguiding a work piece. With some of the lighter gauge metals, theoperator should be cautioned to remove his hands from the work piece assoon as it is engaged between the flanging rolls 33, 39, otherwise theoperator may inadvertently restrain the free self-steering movement ofthe work piece through the flanging machine and interfere with itsaccurate flanging.

At the outlet side of the flanging rolls 33, 39, a follower force isexerted against the outer side of the formed flange. I have indicatedthat the force required is greater for edges of convex curvature, anddecreases as the radius increases. If the edge curvature is concave, therequired follower force is lessened. For straight pieces, someintermediate amount of force is required.

Follower force is exerted by the follower roll 52, which is held againstthe formed flange of a work piece as it emerges from the flanging rolls33, 39. The force is derived from the weighted control bar 61, andvaries in magnitude as the bar 61 responds to the position of thefollower roll 52. With the follower roll 52 pressing against a flangedconvex edge having a small radius, its perimeter will be close to theprincipal flanging roll 33, as in Figure 5, and the control bar 61 willbe in the downward position, as shown in Figure 2. In such position thetrolley 59 at the lower end of the cable 57 will have rolled toward thepivot 62, against the adjustable stop collar 63. Being relatively closeto the horizontal pivot 62, the trolley 59 will be subjected to arelatively large force in order to balance the weighted control bar 61.In this manner, a relatively large force is exerted by the follower rollwhen in position near the principal flanging roll, which position itwill assume automatically when ever the edge against which it bears isconvex.

If the edge curvature should change to concave, the follower roll 52will be forced farther away from the principal flanging roll 33 toapproach the extreme position shown in phantom lines in Figure 1. Insuch extreme position the flanging machine will flange edges havingconcave curvature of as small radius as the radius of the supptementaryflanging roll 39.

Referring to Figure 2, the position of the weighted control bar 61 forforming such small concave-curved edges is shown in phantom lines. Thetrolley 59 is shown to have moved along the control bar 61 outward fromthe pivot 62 to a point adjacent the weight 64 (whose position isadjustable for variations in material strength and gauge). In theposition shown in phantom lines, a much smaller force in the controlcable 57 will balance the moment of the weighted bar 61 about its pivot62. Hence, in following a flanged edge having concave curvature, thefollower roll 52 will press against such edge with a sub" stantiallylesser force than in following a convex edge.

I have previously mentioned that the entire follower mechanism, whoseoperation has just been described, may be dispensed with by a workmanpossessing a degree of skill, who may exert a follower pressure with hisfingers against the piece as it emerges on the outlet side of theflanging rolls 33, 39. To vary such force with edge curvature, in anattempt to duplicate the results of the follower mechanism hereof, mightseem to call for unusual effort. In practice, it has proved to be notdifficult; far less exacting, for example, than the skill which wasformerly required to guide a work piece through flanging rolls. This isbecause the guiding function is handled entirely mechanically, andtherefore follower pressure is of secondary importance.

The depth of flanging is controlled by the collar rim 38; as the metaledge is flanged over sufliciently to contact this rim, its reactionagainst such bent edge prevents overflanging. Should the flange formedbe uneven, or should the work piece be accidentally dislodged from themachine, the piece may be reinserted, and a second or third pass throughthe machine will re-work the flanged edge to correct the initial error.

If it is desired to remove the work piece from the flanger at any timeduring the flanging operation, this may be done by pressing downward thehandle of the lift fork 47. The support yoke 46 and lift bearing 45therein will thereby raise the supplementary shaft 25; and thesupplementary flanging roll 39 will be thrust upward, as shown in Figure3, separating its surfaces sufficiently from the principal flanging rollto permit easy removal of such work piece.

The mechanism described represents a substantial advance, not onlyinsofar as it accommodates pieces of reversing curvature, but socompletely takes charge of the operation that the operator has nothingto do other than start the piece into the machine. While a relativelylong work piece is progressing through the machine, the operator mayleave it to pick up another work piece to be flanged.

Other embodiments of the inventive principles herein disclosed will beapparent to those skilled in the art. Accordingly, the present inventionis to be considered as fully co-extensive with the inventive principlesherein disclosed.

I claim:

1. A flanging machine for sheet metal work pieces, comprising aprincipal flanging roll mounted on the end of a first shaft, its endsurface opposite the shaft being substantially perpendicular to theshaft axis, the said roll further having a perimeter roll surface at aflanging angle to the said end surface, further comprising asupplementary flanging roll, rotatably mounted adjacent the principalroll and having a perimeter roll surface adapted for flanging sheetmetal in cooperation with the said perimeter surface of the principalroll, the said supplementary roll further having a rim overlapping thesaid end surface of the principal roll and having a lesser coeflicientof friction, means for exerting pressure between the said rim and thesaid end surface whereby to grasp a sheet metal piece, means for drivingthe principal roll rotatively whereby to propel such sheet metal piecethrough the flanging rolls, the principal roll being by said meansrotated in one sense by which is established an inlet side and an outletside, a tendency to rotate in the same sense being imparted to such.sheet metal work piece by the greater coeflicient of friction of theprincipal roll, and an edge guide abutment adjacent the inlet side ofthe said fianging rolls and adapted to oppose such rotative tendency andthereby guide such sheet metal piece through the rolls regardless ofvariation in curvature of its edge.

2. A fianging machine for sheet metal. work' pieces, comprising aprincipal fianging roll mounted on the end of a first shaft, its endsurface opposite the shaft being substantially perpendicular to theshaft axis, the said roll further having a perimeter roll surface at afianging angle tothe said end surface, further comprising asupplementary fianging roll, rotatably mounted and having a perimeterroll surface adapted for fianging sheet metal in cooperation with thesaid perimeter surface of the principal roll, the said supplementaryroll further having a rim overlapping the said end surface of theprincipal roll, the surface of said rim having a lower frictionalcoeflicient than the said principal roll end surface, means for exertingpressure between the said rim and the said end surface whereby to graspa sheet metal piece and impart to it a tendency to adhere frictionallyto and rotate with the principal roll, means for driving the principalroll ,rotatively in one sense, and a guide abutment adjacent a linesubstantially tangential to the said flanging rolls and adapted to stopthe edge of such sheet metal piece from rotation and thereby guide suchpiece through the fianging rolls.

3. A fianging machine as defined in claim 1, together with means forseparating the fianging rolls to permit the insertion of such a sheetmetal piece between the rim of the supplementary fianging roll and thesaid end surface of the principal fianging roll with the edge margin ofsuch sheet metal piece engaged between the perimeter roll surfaces ofthe said fianging rolls.

4. A fianging machine as defined in claim 1, together with aself-positioning follower at the outlet side of said fianging rolls, thesaid follower being pressure-urged against the outer side of the flangeso formed.

5. A fianging machine as defined in claim 4, together wtih means toincrease the pressure of said follower as it nears the side of theprincipal fianging roll and to decrease such pressure as it is heldfarther therefrom.

6. A flanging machine for sheet metal work pieces, comprising aprincipal fianging roll mounted on the end of a first shaft, the surfaceof its end opposite the shaft being tooled for increased surfacefriction in a rotary direction, said roll further having a perimeterroll surface at an angle to the tooled surface, a supplementary fiangingroll mounted on a second shaft, the axes of said shafts lyingsubstantially in a plane, said supplementary roll having a perimeterroll surface adapted for fianging sheet metal in cooperation with theperimeter surface of the principal roll, the supplementary roll furtherhaving 7 a rim overlapping the tooled end surface of the principal roll,means for separating the said rolls to permit the insertion of a sheetmetal piece between the said rim and the said tooled end surface, insuch manner that the edge margin of such sheet metal piecelmay beengaged between the perimeter roll surfaces of said principal andsupplementary rolls, means for exerting pressure between the said rimand the said tooled end surface whereby to grasp such sheet metal pieceand impart to it a tendency to rotate with the principal roll, means fordriving the principal and supplementary rolls rotatively in oppositesenses by which is established an inlet side and an outlet side for thefianging rolls, and a guide abutment having a flange-starting sideleading to the inlet side of said rolls and adapted to stop the edge ofsuch sheet metal piece from rotation and thereby guide such piecethrough the rolls.

7. A flanging machine as defined in claim 6, together with a followeradapted to exert pressure against the outer side of a flange formed on awork piece passing through the said fianging rolls, and arcuatefollowerpositioning means adjacent the perimeter roll surface of thesupplementary fianging roll at the outlet side of said fianging rolls.

8. A fianging machine according to claim 6, the said driving meansincluding a source of rotary power and power-transmission means drivingthe said shafts simultaneously.

'9. A fianging machine according to claim 6, the said driving meansbeing so coupled to the said fianging rolls as to drive them at the sameperimeter speed.

10. A fianging machine according to claim 1, together with a followerroll at the outlet side of the said fianging rolls, mechanismestablishing a follower roll path from -a point adiacent the perimeterroll surface of the principal fianging roll outwardly a greater radialdistance therefrom, and mechanism for exerting a force on the followerroll urging it along said follower roll path toward the perimeter rollsurface of the principal fianging roll, against the outer side of aflange formed by said fianging rolls on such a work piece.

11. A fianging machine according to claim 10, together with means forlessening such urging force on the follower roll as its radial distancefrom the principal fianging roll is increased.

1 2. A fianging machine according to claim 6, together with mechanismexerting a force on said follower roll urging it along an arcuate pathtoward the outer side of a flange formed of such a work piece, andmechanism whereby such force is lessened as the position of saidfollower roll along the said path is removed increasingly farther fromsaid principal fianging roll and whereby such force is increased as theposition of said follower roll along said path approaches closer to saidprincipal fianging roll.

13. A fianging machine for sheet metal work pieces, comprising a frame,a rotatively powered fianging roll mounted thereon having a perimetersurface adapted for fianging and an end surface adjacent which one faceof a sheet metal work piece may be pressed, yieldable means for exertingforce against the opposite face of such a sheet metal work piece wherebyits first-named face is pressed into frictional engagement with the endsurface of the fianging roll, the said end surface having a highercoeflicient of friction than that of said force-exerting means wherebyto propel such work piece and impart to it a rotative tendency, togetherwith complementary fianging means positioned spacedly adjacent theperimeter surface of the powered fianging roll for admitting andflangingtherebetween the edge of a sheet metal work piece so pressed,and an edge guide mounted to the frame outwardly adjacent a linesubstantially tangent to the fianging roll at the side thereof fromwhich such a work piece may be admitted, the said edge guide beingadapted to abut the work piece edge to be flanged and to oppose the saidrotative tendency.

14. The combination with a sheet-fianging mechanism, which comprises apair of rotatably mounted cylindrical elements arranged and constructedto grip and feed the flange formed on the sheet, means for guiding theadjacent portion of the sheet including a flat end surface on one ofsaid cylindrical elements and a second flat surface located insubstantial parallelism to said first named surface and cooperatingtherewith in guiding the sheet, and a guide abutment having aflange-bending side leading to the inlet of the cylindrical elements,ofa follower mechanism comprising a follower roll located at the outletof the cylindrical elements and arranged to engage the same side of theflange as the flange-bending side of the guide abutment, a mounting axisfor the follower roll, supporting means for said mounting axismaintaining the fol-lower roll at the level of the flange, saidsupporting means being movable in a plane perpendicular to said axis,and yieldable variable force-exerting means urging said supporting meanstoward the flange with decreasing force as the follower roll is movedoutwardly away from the cylindrical element which has the first namedflat end surface and maintaining the follower roll in pressureengagement against such flange.

15. A sheet-flanging mechanism as defined in claim 14, saidforce-exerting means including a weighted bar hinged at a fulcrum, atrolley wheel movable therealong, and mechanism connecting said trolleywheel and the follower roll supporting means in operating relationshipwhereby the trolley wheel will be drawn further from the fulcrum as theflange directs the follower roll away from said cylindrical elementwhich has the first-named flat end surface.

16. The combination with a sheet-flanging mechanism, which comprises apair of rotatably mounted cylindrical elements arranged and constructedto grip and feed the flange formed on the sheet, means for guiding theadjacent portion of the sheet including a flat end surface on one ofsaid cylindrical elements and a second flat surface located insubstantial parallelism to said first named surface and cooperatingtherewith in guiding the sheet, and a guide abutment having aflange-bending side leading to the inlet of the cylindrical elements, ofa follower mechanism comprising a follower located at the outlet of thecylindrical elements and arranged to engage the same side of the flangeas the flange-bending side of the guide abutment, supporting means forthe follower, said supporting means being pivoted swingably about theaxis of the other of said cylindrical elements and defining an arcuatepath for the follower in a plane substantially at the level of theflange, said arcuate path having a portion nearer the cylindricalelement which has the first named flat end surface, in which nearer pathportion the follower is accommodated in following flanges of convexcurvature, and having a path portion farther therefrom in which thefollower is accommodated in the following flanges of concave curvature,and yieldable variable force-exerting means urging the follower towardand maintaining it pressed against the flange with a greater amount offorce when the follower is in the nearer path portion and a lesseramount of force when the follower is in the farther path portion.

References Cited in the file of this patent UNITED STATES PATENTS711.471 Chamber et a1 Oct. 21, 1902 1,359,197 Ray Nov. 16, 19201,426,253 Bremer Aug. 15, 1922 1,613,307 Bittner Jan. 4, 1927 1,691,032Bittner Nov. 13, 1928 1,733,199 Meyers Oct. 29, 1929 2,084,395 HellerJune 22, 1937 2,194,114 Embree Mar. 19, 1940 2,308,432 Johnson Ian. 12,1943 FOREIGN PATENTS 19,847 Great Britain of 1904

